//update img
function onUploadImgChange(sender,upLoadMapId,upLoadMapWidth,upLoadMapHeight){
	if( !sender.value.match(/.jpg|.gif|.png|.bmp/i)){//允许的图片格式为.jpg|.gif|.png|.bmp
		 
		var uploadObj=document.getElementById(upLoadMapId);
		var uploadTdObj=document.getElementById("uploadTd");
		var newUpLoad=uploadTdObj.innerHTML;
		//清空之前选择的文件

		uploadTdObj.removeChild(uploadObj);
		uploadTdObj.innerHTML=newUpLoad;
		//清空长宽值

		document.getElementById(upLoadMapWidth).value="";
		document.getElementById(upLoadMapHeight).value=""
		var strTxt = "image format is invalid!"
		alert(strTxt);
			//alertMsg("",strTxt,0);
		return false;
	}
	
	var objPreview = document.getElementById('preview' );
	var objPreviewFake = document.getElementById('preview_fake' );
	var objPreviewSizeFake = document.getElementById('preview_size_fake' );
	if( sender.files &&sender.files[0] ){
	  objPreview.style.display ='block';
	  objPreview.style.width ='auto';
	  objPreview.style.height ='auto';
	 
	  // Firefox 因安全性问题已无法直接通过input[file].value
	  objPreview.src =sender.files[0].getAsDataURL();
	}else if(objPreviewFake.filters){
	  // IE7,IE8 在设置本地图片地址为 img.src 时出现莫名其妙的后果
	  //（相同环境有时能显示，有时不显示），因此只能用滤镜来解决
	 
	  // IE7, IE8因安全性问题已无法直接通过 input[file].value 获取完整的文件路径

	  sender.select();
	  var imgSrc =document.selection.createRange().text;  
	  objPreviewFake.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src= imgSrc;
	  objPreviewSizeFake.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src= imgSrc;  
	  autoSizePreview( objPreviewFake,objPreviewSizeFake.offsetWidth,objPreviewSizeFake.offsetHeight,upLoadMapWidth,upLoadMapHeight);
	  objPreview.style.display ='none';
	  objPreviewSizeFake.style.display="none";
	}
}


function onPreviewLoad(sender)
{autoSizePreview(sender,sender.offsetWidth, sender.offsetHeight);}


function autoSizePreview( objPre, originalWidth, originalHeight,upLoadMapWidth,upLoadMapHeight){
	var zoomParam = clacImgZoomParam( 100, 100, originalWidth,originalHeight);
	objPre.style.width = zoomParam.width +'px';
	objPre.style.height = zoomParam.height +'px';
	objPre.style.marginTop = zoomParam.top +'px';
	objPre.style.marginLeft = zoomParam.left + 'px';
	var widthMap=document.getElementById(upLoadMapWidth);
	var heightMap=document.getElementById(upLoadMapHeight);
	if(originalWidth!=0&&originalHeight!=0){
		widthMap.value=originalWidth;
		heightMap.value=originalHeight;
		}
}
function clacImgZoomParam( maxWidth, maxHeight, width, height ){
	var param = { width:width, height:height, top:0, left:0 };
	if(width>maxWidth || height>maxHeight ){
	  rateWidth = width /maxWidth;
	  rateHeight = height /maxHeight;  
	  if( rateWidth > rateHeight){
		  param.width =maxWidth;
		  param.height = height /rateWidth;
	  }else{
		  param.width = width /rateHeight;
		  param.height =maxHeight;
	  }
	}
	
	param.left = (maxWidth - param.width) / 2;
	param.top = (maxHeight - param.height) /2;
	return param;
}